What is Rubble Stone?
Also known as: Rubble masonry; rubblework; rubblestone
When using stone in outdoor building projects like walls, there are usually three different types: flagstone, ashlar and rubble. Rubble consists of stone that is different sizes, textures and shapes, arranged and held together with mortar, which serves as sort of a grout (in tile work) to fill in seams and adhere the pieces together.
If you've seen a demolished building, the waste or rough pieces of stone, brick, or concrete are actual rubble.
In contemporary outdoor projects, these irregular fragments of rock look appropriate in settings that call for earthy, natural, rural or antique walls. They are the antithesis of sleek, machine-made modernism.
Rubble walls have been built for centuries. Traditionally, it was a common practice to use a variety of small stones when constructing rubble stone masonry walls. These small stones were called pinnings, and helped to make larger stones more stable and secure in the wall. This gives rubble walls their distinct appearance - varied, sometimes uneven, and rustic.
Repointing
In older rubble walls, the mortar often has washed away or deteriorated and needs to be replaced. This causes the stones to become loose, especially the smaller ones. If left alone, the wall can eventually collapse. To prevent this, lime-based mortars are used to replace old mortar, as they allow the walls to "breathe" rather than keeping moisture trapped inside.
Scaffolding (like a wire cage) is built over the rubble wall to be repaired to ensure the job is done safely.
Decayed mortar is removed carefully with a hammer and chisel to break away previous mortar and cement, or thin metal tools are used to rake out the old mortar. During this process some of the small pinning stones will fall out. The raked-out areas will then be flushed with water to clean things out entirely.
Repointing starts with pushing new mortar back into the wall, between all the assorted stones. Care and skill are required to to ensure that the mortar fills in crevices, but that the final result is not overly smooth. It is also during this process that loose stones or pinnings are replaced to give the wall structural strength and to give the wall its rustic, rubble-like appearance.
When using stone in outdoor building projects like walls, there are usually three different types: flagstone, ashlar and rubble. Rubble consists of stone that is different sizes, textures and shapes, arranged and held together with mortar, which serves as sort of a grout (in tile work) to fill in seams and adhere the pieces together.
If you've seen a demolished building, the waste or rough pieces of stone, brick, or concrete are actual rubble.
In contemporary outdoor projects, these irregular fragments of rock look appropriate in settings that call for earthy, natural, rural or antique walls. They are the antithesis of sleek, machine-made modernism.
Rubble walls have been built for centuries. Traditionally, it was a common practice to use a variety of small stones when constructing rubble stone masonry walls. These small stones were called pinnings, and helped to make larger stones more stable and secure in the wall. This gives rubble walls their distinct appearance - varied, sometimes uneven, and rustic.
Repointing
In older rubble walls, the mortar often has washed away or deteriorated and needs to be replaced. This causes the stones to become loose, especially the smaller ones. If left alone, the wall can eventually collapse. To prevent this, lime-based mortars are used to replace old mortar, as they allow the walls to "breathe" rather than keeping moisture trapped inside.
Scaffolding (like a wire cage) is built over the rubble wall to be repaired to ensure the job is done safely.
Decayed mortar is removed carefully with a hammer and chisel to break away previous mortar and cement, or thin metal tools are used to rake out the old mortar. During this process some of the small pinning stones will fall out. The raked-out areas will then be flushed with water to clean things out entirely.
Repointing starts with pushing new mortar back into the wall, between all the assorted stones. Care and skill are required to to ensure that the mortar fills in crevices, but that the final result is not overly smooth. It is also during this process that loose stones or pinnings are replaced to give the wall structural strength and to give the wall its rustic, rubble-like appearance.
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